<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script src="js/jquery-3.5.1.min.js" type="text/javascript" charset="utf-8"></script>
		<script type="text/javascript">
			$(function(){
				$("button").click(function(){
					console.log("button")
				})
				$("select").click(function(){
					console.log($(this).val())
				})
				$("#txt").blur(function(){
					if($(this).val()==="")
					$(this).val("账号")
				})
				$("#txt").focus(function(){
					if($(this).val()==="账号")
					$(this).val("")
				})
				
				$("button").hover(function(){
					$(this).css("color","red")
				},function(){
					$(this).css("color","black")
				})
				
				$("#txt").on("click dblclick",function(){
					console.log(1)
				})
			})
		</script>
	</head>
	<body>
		<div class="div">
		<button type="button">点击</button>
		</div>
		<select name="">
			<option value="1">足球</option>
			<option value="2">篮球</option>
			<option value="3">乒乓球</option>
		</select>
		<input type="text" name="" id="" placeholder="iiiiii" />
		<input  type="text" id="txt" placeholder="账号" value=""/>
		<td>点击</td>
	</body>
</html>
